Coining blade forging



June 1954 A. v. D. WILLGOOS COINING BLADE FORGING Filed Sept. 24

IN VEN TOR.

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Patented June 8, 1954 COINING BLADE FORGINGQ Andrew V. D. Willgoos,deceased, late of West Hartford, Conn., by Hartford National Bank andTrust Company,

assignor to United executor, Hartford, Conn., Aircraft Corporation, EastHartford, Conn., a corporation of Delaware Application September 24,1949, Serial No. 117,572

This invention relatesto the manufacture of vanes for use particularlyin compressors or turbines of gas turbine power plants.

Both the stationary vanes of compressors and turbines as well as themovable vanes or blades must be shaped to final size within relativelynarrow limits. While some of the vanes are made from readily workedmaterial, the blades and nozzle vanes of the turbine, which aresubjected to very high temperatures, are preferably made from hightemperature alloys which are diflicult to forge or to machine. When thevanes are forged to size, the dies used in the forging process havelasted only a short time because of the difiiculties in forging thematerial. A feature of this invention is a forming method by which tomaintain the advantages of the forged vanes and at the same timeincrease the life of the dies used in the forming process.

The necessary close tolerances for stationary and rotary vanes incompressors and turbines frequently approach the limits of accuracypossible inforging even under favorable forging conditions. When thematerial of the vanes is difficult to forge, the required tolerancesmake almost impossible the forging of the vane to the desired finisheddimension without the necessity for additional machining to the desireddimension. A feature of this invention is to relieve the forgingoperation of such close tolerances by forging the vane to a smaller-thanfinished dimension and to tolerances readily obtainable by the forgingoperation, withthe finished dimension obtained by a later process.

Another feature of the invention is the coining of the vane to finisheddimension, the outer surface of the vane being a material readilyadapted for coining. Another feature is the forging of the vane to anundersized dimension and subsequently coining the vane after a coatinghas been applied.

Other objects and advantages will be apparent from the specification andclaim and from the accompanying drawings which illustrate an embodimentof the invention.

Fig. 1 is a plan view of the finished blade.

Fig. 2 is a sectional view along line 22 of Fig. 1.

Fig. 3 is a sectional view through the blade and the initial formingdies.

Fig. 4 is a diagrammatic view of the blade coating operation.

Fig. 5 is a sectional view showing the coining operationdiagrammatically.

The invention is shown in conjunction with a 1 Claim. (01. 29-1563)turbine blade or vane adapted to be mounted on the turbine rotoralthough it will be understood that the invention is equally applicableto the stationary vanes or the blades of the turbine or the compressor.As shown in the drawings, the turbine vane has a root section 2 fromwhich extends the effective blade or vane section 4.0ver which the gasflows in the power plant. In the arrangement shown, the entire vane hasa core 5 made from a high temperature alloy to which acoating 8 has beenapplied. The coating is a material which is more readily workable thanthe material of the core so that the coating may be shaped to sizebetween dies in producing a finished dimension and shape for the vane.The material of the coating 8 in addition to being more readily workableis also preferably a material resistant to the action of the ingredientsin the power gas as it passes through the turbine. One material suitablefor this purpose might be nickel.

In producing a vane in accordance with the invention, the core 6 isfirst forged between dies it to approximately the finished shape of thevane but to a dimension which is undersized from the desired finisheddimension for the vane. It will be understood that the tolerancesestablished for the dimensions of the core when forged are tolerancesthat are readily obtainable by the forging operation even though thematerial is one of the high temperature alloys which is difiicult toforge. By forming the core in this manner and with liberal tolerances indimension, it is possible to use the forging dies in producing arelatively large number of vanes before the dies become so inaccurate asto require replacement.

The core 6, having been forged, any flash thereon at the edges of thedies is removed and the coating 8 is then applied either by spraying thematerial on or by electroplating the core as shown in the drawing. Thecoating 8 which is applied is not necessarily the exact shape anddimension of the finished vanes and this coating is shaped by a forgingprocess to precisely the desired shape and finished dimension of thevane. Although this forging process may be any one of several which willproduce the desired dimension, the particular forging process shown is acoining process in which the dies l2, which are the finish dies, act tocoin the material of the coating 8 and produce the exact shape anddimension with no excessive material that might produce a flash aroundthe edge of the vane.

The coining process is selected since the material of the coating may beselected such that it will be readily coinable without reference to itsstrength at high temperatures since the core can function as the loadcarrying part of the vane.

It is to be understood that the invention is not limited at()' thespecific embodiment-hereini'illustrated and'described-but may beuseddnother ways without departure from its spirit as defined by the followingclaim.

What is claimed is:

In the manufacture of a vane for a compressor or turbine, the vane beingo'f a high temperature material which is difiicultto forgefithe stepswhich involve forging theTYanE7tOth6'd85iI'ed shape and to a slightlysmallerthanefinishedi dimension, trimming any flash from the edges ofsaid forged vane, coatingesaid'nvanetmitrra coinable material havingcorrosion .resistant characteristics, the coating being enough inquantity to produce the desired finished dimension of vane, and coiningsaid vane to said finished shape and dimension, said coining operationleaving said vane free from flash.

References Gited in-the file of-this "patent UNITED STATES PATENTSNumber Name Date 13561 900 Becket Nov. 17, 1925 ..2;058,841 .fIhomsonOct. 27, 1936 :-;2,29.3;768 .ffichaefer Aug. 25, 1942 2125031630IELNOTEOH Apr. 11, 1950 "-'FG)REIGN PATENTS -.-Number isflountry DateGreat Britain Sept. 29, 1932

